Maps exercise from ["A Tour of Go"](https://tour.golang.org/welcome/1)

exercise_maps.go

package main

import (
	"fmt"
	"golang.org/x/tour/wc"
	"strings"
)

func WordCount(s string) map[string]int {
	// create a slice of strings with each of the inputs
	var fields []string = strings.Fields(s)
	
	// initialise the map variable for storing the results
	duplicate_frequency := make(map[string]int)
	
	// iterate over each value in the field (ignore the index)
	for _, item := range fields {
		
		// does the key exist?
		_, exist := duplicate_frequency[item]
		
		
		if exist {
			// increment counter
			duplicate_frequency[item] += 1 
		} else {
			// start counter
			duplicate_frequency[item] = 1 
		}

	}
	return duplicate_frequency
}

func main() {
	wc.Test(WordCount)
}